Governments are not doing enough to prevent the spread of invasive species.

Part of the problem is the massive international trade in live (or dead unsterilized) plants and animals. There are so many opportunities for a weed to tag along. Why not require safety inspection of every cargo?

The ballast water of ships often carries invasive aquatic organisms, often as larvae. Why not have an official go aboard while the ship is 20 miles out, to require it to clean its ballast tanks?

These measures would be expensive, but so are invasive species.